N-acetyl-L-aspartic acid (NAA) is present in high concentration in the free amino acid pool of the nervous system of the higher vertebrates such as man, the rat and the chicken. The objectives of this project are: (1) To isolate and characterize the enzymes involved in the metabolism of NAA and to determine the tissue distribution and developmental pattern involved; (2) To study the factors which induce the enzyme activities in various tissues; (3) To study the transport of NAA into various cell types such as glia and neurons and cell particulates such as synaptosomes; (4) To study the enzyme activities, transport and other processes involving NAA in abnormal states such as hypothyroidism and malnutrition; and (5) To determine the direct precursors of the C4 and C2 fragments of the molecule in brain slices, glia and neuronal cell bodies and to extend this work to various other tissues and organisms.